Hydraulic valve control



Jan. 28,1958

R. A wrm-REN HYDRAULIC VALVE coNjrRoL File March 19. 1956 United States Patent() 258215211: HYDRAULICVALVETCONTROL Richard A. Wttren; (Zodat-Falls, Iowa, assgnor4 to V'Deere Manufacturing? (2oz, ADl1!.'n1qne,.Iowa,A a corporation of Iowa Application Maren 19; '1956; sel-ama.' 572,576,

'81Claims-.-l (Cl.";13.7"622;`5)

This invention relteszto alhydraulcvalvecontrol and more particularly toa control "systemin Whichacontrol.

elementor lever` is automatically. returnedto neutral after a certain-amount of`travel of amotor controll'ed'byl the valve.

The g'eneralfeatureV ofautomaticr'eturn to neutral has heretofore been exploited in many 'diierent ways, the

fundamental object beingto'provide a control element movable in one directionl through a range including neutral, intermediate or slow and'naximum'or fast positions, with the further'provision of'means` biasing the control element'for return to neutralfr'om. its intermediate or slowY position, plus releasable detent' means for releasably locking theV control element in 'its maximum or fstapos'ition until'a predeterminedi'amount oftravel of the motor has been obtained. In one, arrangement, the attainment -by the motor'of its. predeterminedamountV of travel incurs an. abnormal increase in pressurein the system,.with`the result that the relie'valve, through'appropriate mechani- `cal linkage, releases or 'overcomesl the detent'andthe biasing means returnsthercont'rol elementi to its neutral position. The problem iny any'caseis" onei'of balancing the d'etent meansagainst the "biasingreturn means, it"b` eing clear that if the det'eot means is stronger than the biasing means; some mechanical'or hydraulio'device' is necessary to overcome'the detentmeans. lfthe return vbiasing means is stronger than the detent means,I then theeiect of the detent is nnllied.

'According to tlepresent invention, itA is a'principal object to utilizeu a` strongerv return biasing nreansfbntL to employ'hydranlic forces for overcoming/atleast `apart of the' eir'ect Yor "the biasing means` so las* to render the detent means effective. The' accomplishment of-this objectenltails the utilization of uid-respons'ive/means incorporatingY a"lnid4pressuredierential areaiandf thecontrol of `the duid through-'a pair 'of restrictionsinseries; plus' the control of the restrictions so as to utilize-the pressure drop across the restrictions'forv creatingalconditi'on of hydraulic unbalance-acrossithe differential area. 'Itis a furtherobject of thisfinventionitofrutilize" theiforegoing principles "in a simple and economical' valve-arrangement vthat may/be readilynsed vwitheanyf'ftype of hydrauliesystem, Whether' variable or constant displacement.

Thel'foregoing andother important objects and desirabie features 'inherent' inw and encompassed bythe inven- 'tion will become apparent to thosev versediiri` the'arteas a f preferred embodiment of"Y lthe invention! 1's disclosed in vdetail'in the ensuing specification andaccompanying sheet Aof drawings, the'sleveral-gurs ofrvvhichf willfbe described immediately below.

Pig. lv is a: schematic View, partly in section, showing Aan 'over-all hydraulic' system .incorportingthe improved vfvalve control.

rigsizjsand 4am enrafgdseenenar viewsl affette of the valves, inustranng .the various stages of'operanon of the system.

"lior the purposes 'of the present' case, aA` single valve,

2,821,211 Patented Jan. 258, 1958 vc':as'i1:lg' 10 is Vshown as containinga plurality ofxnulti-part valves 12, 14, 16 and 18 for controlling-a uid circuit including apyump P, a reservoir R anda'motor- M'ofethe cylinder and'piston type including acylinder-^20and a piston'ZZ'. vThe four valves are under controllof aconltrol'elementor lever 24, pivotally mountedongthe'housing on a fulcrum 26, for movementto either'sideoffy a neutralv position Nfamong either oftwo `slowpositions S 'andftwo fastor maximum-positions?. Thecontrol-ele- 'mentl has detent means 23 cooperative selectively with `either-oftwo notches-30 for-electingreleasable lock of thegcontrol' element in one or the'otherof-=the fastv or maximum positions F. Therangeincluding the distance 'between the two intermediate orsslow positionseSis determined by a pair of lugs'32, either of'ewhich mustl be vpassediby the detent means '28gin order toattainthenext Aadjacent fast-position F. Biasing'rneans included inthe valiesf`1214if16 Aand 18, to be presently describedindetail, operate tomaintain the neutral-orN position ofthe lever: or element 2 4.

Althoughtlieesingle valve casing 1 0I is illustrated, it

lwill b e understood: that fthecasing structure itself 'may be oftany type andfthatishown-is for purposes ofillustration only.- Onlthatbasisf, the pump is connected to` the casing' 10fvia la-high-pres'sure line 34 having-a pairof highpressure branch passages l36 and 38. The v passage 536 intersects a valvechamber'y 4W for the Valve 12, andthe passage S'intersectsay similarv valve chamber 4 2 fori the valve- 14Al Thevalvei chambers-'401 and 42 are respectively in `communication'with other passages y@tand- 46 which "ultimately-'lead respectively toL oppositeendsofthe cylin- Vder-20'A ofthe-motor M, the-'passage44 intersectinga valve chamber 48 for the valvel and-the passage-46lintersec ing -a valve chamber v50 for thevalve 18; The'valve 4chamber 48 communicates With-a reservoir branch-passage 52 and a similar relationship exists-between- Vthe valve 'chamber150 and a reservoir branch passage'54,-the two reservoirbranches leading in common ati-56 to the reserv'o'ir R.

The valves 1v21and 14'arefofidenticall construction and are symmetrically arrangedy `in the -casing 10', respectively at 'Opposite sides of the upper arm ofthe valvecontrol element24'. Thevalves 16 and v1'8, although rt hey;may-be identical-to the valves 1 2 and 14, need not include all therenements, as willpresently appear. lForl the purposes of the present disclosure, it isdeemedsucientto de-ne in detail Vjust the valve'1 2, it bein-g understood that ft-he'valve 1 4 is similarly constructed. "Thediierences be- -tvveenthe valves 12 and 14 and the valves 1 6-and lS-Will be brought out as the descriptionV progresses.

As best-seen in Figs. 2, 3 and 4,'-t'he mnltiLpart valve 12'` comprises an outer valve par-tv 5870i stepped construction, havinga -large portion 60, a. small portion`62`and an intermediate portion 64 interconnecting thegportions 60-and 62. The valve casing has a small bore l66fconthe intermediate portion 64 and the small portion-'6 2 affords an annular conical shoulder 76 which is seatable von and unseatable from' the main valve seat 68. Biasing means in the form of a spring 7 8 normally maintains the Iseated oriclosed condition of the outer valve 'par/:58.

The outer valve'part 58 is tubular tcp-accommodate the spring 78 and therefore opens at its opposite ends re-v spectively to the passage 44 and to the counterbore 70. The outer valve part further has therein an inner valve seat 80 on which an inner valve part in the form of a ball 82 is seatable and from which the ball is unseatable, the ball being normally held in its seated or closed position by a relatively light biasing means or spring 84.

An actuator or stem 86 projects from the inner o1 small end of the outer valve part 58 and through an appropriately sealed aperture 88 in the valve casing 10, engaging the upper portion of the control element 24. The stem loosely fits the inner annular surface or bore 90 of the small end 62 of the valve part 58 except for the provision of land means 92 on the valve-contained end of the stern, which land means and the inner surface 90 comprise a pair of regulator portions for purposes to presently appear. The small end 62 of the valve part 58 has a plurality of radial bores 94 for enabling the free interchange of fluid between the bore 90 of the valve and the passage 44. The actuator or stem 86 has an intermediate upset portion 96 Which, in conjunction with the extreme inner end of the small portion 62 comprises force-transmitting means between the valve part 58 and the stem.

When the valve 12 is closed, which means that the control element 24 is in its neutral position, the biasing means 78 acts to seat the outer valve part 58 on the main seat 68 and the biasing means 84 is effective to seat the inner valve part or ball 82 on the inner seat 80, the V main seat 68 being therefore closed against fluid interchange between the passages 36 and 44. Now, disregarding for the moment the features of the present invention, the expected operation of the valve would befas follows: when the control element 24 is moved counterclockwise as seen in Fig. l, to an extent determined by engagement between the detent 28 and the left hand lug 32, the system is set for slow-speed operation, because the stem 86 will, upon being moved inwardly by the control element 24, unseat only the valve ball 82. Slow speed operation is obtained by fluid flow from the passage 36 to the passage 44 via the interior of the valve part 58 and an orifice or restriction 98 in the wall of the intermediate portion 64 of the valve part 58. Movement of the control lever 24 additionally in the same direction, so that the detent 28 yields to the lug 32 and engages the notch 30, would cause engagement between the forcetransmitting means 96 and the proximate end of the valve part 58, incurring unseating of the outer valve part 58 as respects the main valve seat 68, whereupon the rate of fluid ow from the passage 36 to 44 would increase. In either event--whether slow-speed or high-speed operation is obtained-the fluid delivered by the pump would then pass to the left hand end of the motor M, moving the piston 22 to the right.k As the control element 24 is moved in the counterclockwise direction aforesaid,`the lower portion thereof would openthe diagonally opposite valve 18, so that exhaust uid from the right hand end of the cylinder 20 would iiow across the valve chamber to the reservoir branch 54 and thence to the reservoir via the line 56. VAs previously stated,the valve 18 could be identicalrto the valve 12, it being material here only to note that the valve 18 is biased to closed position by a single small spring 100, similar to the spring 84, and that this valve has an actuator stem 102 like the actuator 86. Operation of the system to obtain travel of the piston in the direction just the reverse of that described is obtained by moving the control element 24 in a clockwise direction, in which case the valve 14 is.con trolled via an actuator 104 and the diagonally opposite valve 16 is controlled by an actuator 106. Since the valves 12 and 14 are identical, the valve 14 is backed up by a pair of springs 108 and 11) respectively similar to the springs 78 and 84. The valve 16 is backed up by a single spring 112 like the springs 84, 100 and 110. In any phase of operation, only two diagonally opposite valves are opened, the upper one 0f which SupplieS 4 pump pressure to one end of the motor M and the lower one of which enables the exhaust of uid from the opposite end of the motor.

The value of the present invention may be best appraised by considering that if the detent means 28, when engaged with the left hand notch 30, is stronger than the biasing means at 78 and 84, the biasing means could never overcome the detent without some mechanical or hydraulic force applied thereto, unless the operator manually retracted the control element. As stated above, it is not novel to provide means for automatically overcoming the detent 28. However, there is novelty in the means illustrated Vhere, which utilizes, principally, the regulator portions 90 and 92, which establish one restriction, and the orifice 98 in the outer valve part intermediate portion 64, which eiects a second restriction, the two restrictions being in series and the restriction at 90--92 being variable or controllable to incur pressure drop either across the restriction 90-92 or across Ythe orifice 98, the incurring of the latter of which is important in conjunction with the diierential or Huid-pressurereceivable area 74. By means of the foregoing general principle, hydraulic unbalance is utilized to create a hydraulic force suicient at times to eiectuate the detent, which hydraulic force decays or is vdestroyed in response to the substantial absence of fluid ow through the valve, whereupon the biasing means 78 becomes eifective to overcome the detent 28 and to automatically return the control element 24 to neutral. As an adjunct to the foregoing, the small portion 62 of the outer valve part 58 is equipped with a fluid control portion in the form of a land 114 which requires a higher lift of the valve part 58.

As previously stated, when the multi-part valve 12 is closed, the outer valve part 58 is seated on the main Valve seat 68 and the inner valve part 82 is seated on the inner seat 80, and the control element 24 is in its upright or neutral position. The slow-speed or intermediate position is illustrated in Fig. 3 wherein it will be seen that the actuator 86 is moved inwardly an amount corresponding to angular movement of the control element 24 until the detent 28 engages the left hand lug 32. At this point, the inner valve ball 82 is unseated from the inner valve seat Vand the regulator portions 90 and 92 are cooperative to effect a restriction of substantially smaller area than the restriction'aorded by the valve part orifice 98. Consequently, the etective pressure drop is across the restriction -92 and any hydraulic forces acting on the outer valve part 58 as fluid ows from the passage 36 to the passage 34 are, in conjunction with the biasing spring 78, elective to keep the outer valve part seated on the main valve seat 68. Hence, the rate of fluid ow through the valve is relatively slow and slow-speed operation of the motor M is obtained.

When the actuator 86 is moved farther inwardly (Fig. 4), which corresponds to the position of the control element 24 when the detent 28 passes the lug 32 and enters the left hand notch 30, the land means or regulator portion 92 moves additionally inwardly, not only unseating the valve ball 82V but in eiect destroying the restriction at 90-92, whereupon the restriction or throttling action at 98 becomes effective to create a pressure drop across that orifice 98, whereupon is incurred Aa condition of hydrulic unbalance in which the pressure in the passage 36 is higher than that within the valve part 58, which hydraulic force is thereby utilized to tioat the outer valve part 58 in its opening direction to open the main valve seat 68. 'In its broadest aspects, the invention utilizes the hydraulic unbalance to incur suicient hydraulic force to substantially negative the greater effect of the biasing means 78 as respects the detent 28. That is to say, recognizing that the biasing means 78 must be stronger than the detent 28 to accomplish automatic return of the control element 24 to its neutral position, it 'must also be recognized that if that condition exists alone, the detent 28 'v'vouldlfn ineiective unless'the `forcesactingin opposition thereto are either removed orrminimized. It will be therefore appreciated that the amount of force that is hydraulically removed from the biasing means 78 will determine the effectiveness of the detent. Stated otherwise, if the hydraulic force acting on the area 74 is suicient to balance against the biasing means, then the detent will be elective to maintain the fast or maximum position of the control system and, in order that the biasing means again becomes elective to overcome the detent, the hydraulic force at 74 must be removed. This is accomplished in response to the substantialV cessation of uid iiow through the valve, which follows from the proposition that pressure drop across the orice 98 depends upon the continuation of liuid ow at an appreciable rate. However,fwhen the piston 22 reaches the end of its stroke or its travel is otherwise limited, uid liow through the valve 12 will cease. As it does so, the pressures in the passage 36 and in the interior of the valve 12 become at least balanced, whereupon the spring 78 is effective to return the outer valve part 58 to its seated position on the main valve seat 68. As a practical matter, the design may be so calibrated that the returning or seating forces are substantially greater'than those necessary merely to close the valve part 58, since those forces are utilized, via the force-transmitting means 96 and the end of the small portion 62 of the valve part 58, to act through the actuator 86 for overcoming the detent 28 and for additionally moving the control element 24 back to its neutral position. That is to say, in the absence of fluid ow through the valve, and thereupon in the absence of a pressure drop across the oriiice 98, forces are again available to move the outer valve part 58 to the right from its Fig. 4 position to its Fig. l position.

The land or control portion 114 on the small end 62 of the outer valve part 58 tolerably fits the bore 66 so that maximum liuid ow does not begin until the valve part 58 is unseated a substantial amount from the seat 68. This alords a suicient range of movement of the control element 24 between its slow and fast positions and increases the amount of movement of valve travel sucient to release a conventional detent. Otherwise, the detent would have to be specially constructed. In short, the land 114 is added to obtain a high lift valve without excessive How area. Excessive ow area would not maintain the required pressure drop across the orifice 98 in the fast position of the valve.

Various features of the invention not categorically enumerated herein will undoubtedly occur to those versed in the art, as will modifications and alternations in the preferred structure illustrated, all of which may be achieved Without departing from the spirit and scope of the invention.

What is claimed is:

l. Hydraulic control mechanism, comprising: a valve casing having a first fluid passage, a bore opening at one end to said passage and at its other end having a main valve seat, an enlarged counterbore opening at one end to the valve seat and being closed at its other end, and a second iiuid passage intersecting the counterbore adjacent to said valve seat; a tubular outer valve in the bore and counterbore and traversing the second passage, said valve opening at one end to the closed end of the counterbore and at its other end to the tirst passage and having a large portion slidably fitting the counterbore, a small portion received in the bore and an intermediate portion connecting the large and small portions and reduced as respects the large portion to afford a pressure receivable area exposed to the second passage and enlarged as respects the small portion to afford a shoulder seatable on and unseatable from the main valve seat, said intermediate portion having an orifice therethrough communicating the second passage with the interior of the valve, said valve further having an inner valve seat facing the counterbore;

means biasingithervalve to closethe valve via seating ofsaid-shouldenou the main valve seat; an inner valve seatable on and unseatable from the inner valve seat; means biasing the-inner Vvalve to seat on said inner valve seat; an actuator stemselectively movable within the small portion. of the outer valve to unseat the inner valve in varying amounts; regulator means comprising an inner cylindricalsurface part o said outer valve small portion adjacent totheinner valveseat and land means on said actuator stem closely cooperative with said surface part upon minor unseating of the inner valve to aord a ow restriction of smaller area than the aforesaid orice, so that thepressure drop across the restriction is greater than that across the orifice during uid ow from the second passage to the first passage, whereby the outer valve remains seated, said land means being movable beyond said surface part upon major unseating of the inner valve to enlarge the restriction and thereby to cause a pressure drop across the orifice and consequently a condition of hydraulic unbalance across the pressure-receivable area of the outer valve effective to at least partially overcome the outer valve biasing means until uid liow through the valve decreasesto such extent as to destroy said hydraulic unbalance, .whereby the full force of the outer valve biasing means is again available for re-seating of said outer valve.Y

2. The invention dened in claim 1, in which: the outer valve includes an external uid control portion thereon at one side of the main valve seat and cooperative with the casing to delay substantial uid ow past the main valve seat until the outer valve is unseated from said main seat a substantial amount.

3. The invention defined in claim 1, including: a control element operatively engageable with the actuator for movement in one direction from a neutral position incurring seating of both valves, to an intermediate position incurring minor unseating ofthe inner valve and thence to a'maximum position incurring major unseating of the inner valve; the inner valve biasing means being eiective via the actuator to return the control element to its neutralV position from its intermediate position; said outer valve and actuator having cooperative force-transmitting portions thereon effective upon re-seating of said outer valve by said outer valve biasing means to transmit force to the element via the actuator in the direction of return of said element from its maximum to its neutral position; detent means operative to releasably lock the control element in its maximum position as long as the aforesaid condition of hydraulic unbalance exists on the outer valve; and said outer valve biasing means being stronger than the detent means so as to incur automatic return of said element to its neutral position when the hydraulic unbalance decays upon decrease in Huid ow through the valve.

4. Hydraulic control mechanism, comprising: a valve casing having fluid passages interconnected by a valve chamber; a valve control element movable in one direction through a range including neutral, intermediate and maximum positions; a multi-part valve in the chamber for controlling fluid low across the chamber from one passage to the other and including a main valve part openable to afford maximum fluid ow, a secondary valve part openable selectively in varying amounts to aiord lesser Huid ow, and an actuator part engageable between the secondary valve part and the control element to incur minor opening ofthe secondary valve part in the intermediate position of said element and to incur major opening of said secondary valve part in the maximum position of said element; first biasing means acting via the secondary valve part and actuator to return the element from its intermediate position to its neutral position; detent means operative to releasably hold the element in its maximum position against the force of the rst biasing means; means operative between the main valve part and the actuator part for transmitting force from the main valve p'artto the control, element- -via the-actuator in the direc-V close the'mairr-valve yand operative through said force' transmitting-*meanstoovercome t-he detent means for returning-the'element to neutral position from its maximum position; anduid-responsive-means in the valve operative upon-major opening of thev secondary-valve part and uid flow therethrough to incur a-hydraulic force acting to open the'mairi valve part and to overcome atleast-a part of the-forceof the secondbiasing means so that the detent means-:becomes eiective to maintain lthe element in its maximum position,l said4 huid-responsive l means, responding-to substantial cessation of uid ow through the valve to incurdecayxof; saidhydraulic force, whereby the force of-'thesec'ond biasing-means isagain'available to overcorne4 thel detentmeans.. e t

5. Hydraulic control-mechanismLcomprising: Va valve casinghavingzuid passages interconnected by a valve chamber; ;a valve control element movable in one direction through'aA rangeincluding neutral, intermediate and maximum positions; a valve inthe chamber openable'in varying amounts toafford diierent rates of uid ow from onepassageto the'other; Van actuator part engageable between the valvev and the control element to incur minor and major opening of the valve respectively in the intermediate' f andl niaxirr'iu'm posit-ionsv of said element; biasingmeans acting'on thevalvefand'actuator to bias the element to its neutral position; detent means operativeonly in'thenm'aximum position of the element and constructed to releasably hold'theeleinentrin,itszmaximum position except for the force of the biasing means, said ibiasing 'means bein'g stronger than the detent'means; and Afluid-responsive'means in the valveg operative upon forcibley opening of the valve -by movement of the element toV its maximum position'and consequent'uid-ow therethrough, to incur ahydraulic force acting to increase the amount'of opening of'the'valve and to overcome at least a epart'of the -forceof the biasing means so'that the detent means becomesV eective to'maintain the element in its maximum-position, said'uid-responsive meansV responding tosubstantial-cessation offiuid owthrough the valve to in curdecay of said hydraulicl force, whereby the force of the biasing means is againavailable to Vovercome the ydetent means. Y

6. The invention dened in claim S, in which: the fluidresponsive means comprises a uid-pressure-receivable area on the'valve and a pair of ow restrictions in series through the valve, one; of said-restrictions being variable to select the restriction across which pressure drop is incurred so as to initiate the hydraulic force acting on the valve by means of Vhydraulic unbalanceacross said area.

7. The invention dened in claim 6,-in which: the variation of said one restriction is regulated by the amount of opening -of the valve, said'valve having means providing a substantial restriction upon minor opening of the valve and a lesser restriction upon major opening of the valve.

8.Hydrau1ic lcontrol mechanism, comprising: l a valve'A casingehavingia 'rstfluidpassaga a bore opening at one end-to said-passage-andaat its other end havingramainvalvef seatgjan'enlarged counterbore opening-at one endy to thevalvefseatandrbeing: closed at its'otherend,A anda seconduid passageintersectingzthe counterbore adjacent to said valve-seat; a tubular outeriva-lyein'the bore and counterbore and traversing thesecond passage,v said valve openingat`one end Ato the closed endv of the counterboreand` at itsother/endtothe'irst passage and having a large portion slidably fitting-thel counterbore,` arsmall portion received inthe bore andl an' intermediateportion connecting the large and"smalljportionsand reduced Aas respects the large portion to jatordv apressure receivable area ex'- posed tothe secondnpassage and Aenlarged Las respects the small portion to aifordfa shoulderseatable one'and une seatable from the main valve seat,'s aidintermediateporf tion having an orice therethrough communicating the second passage. with the vinterior of the valve, said valve further having an inner valve-seat facing the counterborejl a coaxial coil springbiasing the valve to close the valve via'seating of said shoulder on the main valve seat; a ballI valve-seatable on and unseatable'from the inner valve seat; a coaxial coil spring within and encircled by the irst'mentioned spring-and biasing the ball to seat on said inner, valve seat; an actuator stem selectively movable Within the small portion of the outer valve to unseat the ballY inva'rying',amounts;l regulator means comprising an innercylindrical'surface part of said outer valve small portion adjacent to--the inner valve seat and an enlarged head on said actuator stem closely cooperative. with said surfacepartupon'minr unseating of the ball to afford a Howl restriction ofl smallerfareathan the aforesaid orice,l so'th'atl the pressurev drop across `the restriction is'greater than that across the orifice duringiiid owfrom'the second passage toth'e `irst passage; whereby the outer valve remainsseated, said'head being movable beyond said surface part upon majorunseatingof the ball to enlarge the restriction and thereby to lcausev a pressure drop across the orifice and consequently a condition of hyraulic unbalanc'e across' the'pressure-rec'eiving area of the outer valveeiectiveto a'tlea'st partially overcome the outervalve biasing means' until uid ilow through the valve decreases to Vsuch extent as to destroy said hydraulic unbalance, whereby the'full'force of the outer valve bias# ing means'is again'available for re-seating of said outer valve.`

References Citedin the le of this patent UNITED STATES PATENTS 2,385,016" Mercier" -l Sept. 18, 1945 

